The advantages obtained from the application of fabric conditioning agents (i.e., fabric softeners and/or antistatic agents) to laundered fabrics are well known. The present invention pertains to particulate softener/antistatic compositions which survive the wash process and release the active softening/antistatic agent to the laundered fabrics in the dryer.
U.S. Pat. No. 4,223,029, Mahler/Doumani, issued Sept. 16, 1980, discloses a product for use in softening clothing in a rotating dryer. Free-flowing particulate softening agent yields a positive charge to the ambient moist air. The softener particulate is in a moist, air-permeable packet.
Fabric softening and antistatic benefits are a desirable part of the laundry process. Softening and antistatic compounds are, in general, quaternary ammonium compounds that are not compatible with anionic surfactants. These compounds will be referred to hereinafter as fabric softening compounds or fabric softeners, although it is to be understood that they deliver both softening and antistatic benefits to fabrics. The opposite electrical charge of the anionic surfactant used in most detergents and the quaternary ammonium fabric softening compounds leads to a mutual attraction which causes precipitation. This, in effect, removes surfactant and fabric softener from solution and reduces the cleaning capacity of the detergent while preventing effective fabric softener deposition on the fabric.
One solution to this incompatibility problem is the separate addition of the fabric softener during either the rinse cycle of the wash or while the fabrics are in the dryer. This increases the inconvenience of using fabric softeners because of the need to add them at a point in the laundering process which is different from that at which the detergent is added.
Various other solutions for this problem of incompatibility between detergent and softening compounds have been proposed in the art. U.S. Pat. No. 3,936,537, Baskerville Jr., issued Feb. 3, 1976, and U.S. Pat. No. 4,095,946, Jones, issued June 20, 1978, both incorporated herein by reference, teach the use of intimate mixtures of organic dispersion inhibitors (e.g., stearyl alcohol and fatty sorbitan esters) with solid fabric softener to improve the survival of the softener in the presence of detergent in the washer so the softener can act on the fabrics when it melts in the dryer. U.S. Pat. No. 4,234,627, Schilling, issued Nov. 18, 1980, teaches microencapsulation of fabric softener. The microcapsules survive the wash and adhere to the fabric surface. They are then ruptured by subsequent tumbling of the fabric in the dryer, thereby releasing softener to the fabrics. Fabric softener prills with a water-insoluble coating are known. However, the commercial production of such softener prills is expensive and delivery efficiency in the dryer can be affected by the coating.
U.S. Pat. No. 4,659,496, Klemm et al., issued Apr. 21, 1987, discloses a dispensing pouch containing premeasured "washer resistant fabric softener . . . chips larger than the pouch valve openings." Klemm et al.'s exemplified softener has viscosity 30,000 to 40,000 cps.
Softeners with viscosities over 30,000 cps have an unacceptable level of fabric staining, low inefficient release in the dryer, as well as residue staining of the pouch from which the softener is delivered.
Thus, there is a continuing need for improved methods and compositions which are more suitable for conveniently and effectively preparing particulate fabric softeners for the home laundering process.
An object of the present invention is to provide a pouched jumbo softener particulate for reduced residual staining of the pouch after use.
It is also an object of the present invention to provide particulate fabric softener which survives the detergent wash solution and releases the softener to the fabrics at dryer temperatures.
Yet another object of the present invention is to provide a softener that will survive the wash process and release in the dryer without need of a coating.
Still another object of the present invention is to provide a softener with efficient softener release in the dryer.